1. Field of the Invention
This invention relates to a radio communication system, a method of radio communication for information provision service, and a mobile radio station, and more particularly, is suitably applied to a code division multiple access (CDMA) cellular system.
2. Description of the Related Art
A cellular system is intended to provide communication services, so that the cellular system does not have sufficient communication capacity to provide services other than communication services. For this reason, data transmission using the cellular system, like facsimile transmission and computer communications using modems, is personally performed only by individual users, therefore information provision services for providing a variety of information from a cellular network have not been particularly performed.
In the United States, a cellular system in accordance with a CDMA scheme have been standardized, and services are going to be inaugurated. The CDMA scheme has also been adopted in a new mobile communication system such as a personal communication service (PCS) and has its position substantially established as a predominant scheme of the next generation in the United States.
The CDMA scheme is characterized by its very large communication capacity as compared with a conventional frequency division multiple access (FDMA) scheme or the like. In the future, one half or more of a 25 [MHz] frequency band assigned to an existing cellular system and a 60 [MHz] frequency band assigned to the PCS system is going to be operated in accordance with the CDMA scheme, whereby it is thought that the CDMA scheme can ensure approximately tenfold communication capacity as compared with that of the conventional schemes. Therefore, in the CDMA cellular system, the essential communication services do not occupy all of the assigned frequency bands, so that highly value added services such as information provision services can be provided.
The CDMA scheme comparatively has large communication capacity, however, the communication capacity of the CDMA scheme is small as compared with that of a wire communication network. This is because the wire network can easily increase the communication capacity only by increasing cables, whereas the CDMA scheme has a limitation in the number of multiplexed codes as well as a limitation in terms of the frequency band. Thus, even with a cellular system in accordance with the CDMA scheme, an efficient service provision must be attempted for its practice.
Also, in order to spread information provision services, it is desirable to increase the amount of information available with the same frequency to conduct efficient service provisions. Further, it is desirable for users that such services provide a good usability.